Skin bacteria could be used to identify you just like your fingerprints. Studies on all the microbes (a.k.a, microbiome) that live in and on the human body suggest that humans serve as hosts for a vast diversity of microorganisms.
Each human being supports trillions of microorganisms and any 2 people share only about 13 percent of their skin bacteria population. While a few of the skin bacteria are harmful and can cause serious illnesses, majority are harmless and beneficial. In healthy individuals, the harmless bacteria (commensal skin bacteria) provide protection from disease causing bacteria (pathogens).
For example, Staphylococcus epidermidis produces antimicrobial substances that help fight pathogenic bacteria and Propionibacterium acnes uses lipids from the skin to generate short-chain fatty acids that can similarly provide protection from harmful microorganisms.
How skin bacteria could be used to identify you
The diversity of bacterial populations living on our skins is much higher (at molecular level) than previously thought and it varies widely from person to person. Recent research has revealed that any two people, on average, share only about 13 percent of their bacterial populations, which also can vary in quantity.
The other 87 percent of the bacteria types are so distinct they act like a bacterial fingerprint and could be used to identify the individual person. When we sleep on beds, shake hands, touch things such as door knobs, ATM keys, a computer keyboard or mouse, we leave behind an identifying trace of bacteria.
What’s more, analysis of skin bacteria could be used to determine how much individuals in a family interacted, what rooms they used, and even when they had last been to one part of the house or another. The skin bacteria population profile has obvious applications in forensic science. The profiles could come in handy to track down criminals or lost individuals.
Another practical application could be to differentiate between identical twins. While identical twins may have the same DNA, chances are that they only share about 13 per cent of their body bacteria populations.
Challenges facing the use of skin bacterial signatures for identification of people
One challenge is that traditional methods of bacteria identification cannot be used to adequately differentiate bacterial populations in or on human bodies. Advanced molecular methods, only available in a few research labs are required. Secondly, if more than one person left their bacteria on an object, it is not yet possible to sort out their mixed-up bacterial signatures.
While use of skin bacteria to identify you is still years away, once perfected, the technique eventually could become an additional forensic tool, along with others like fingerprint and DNA analysis.
- Fierer N, Lauber CL, Zhou N, McDonald D, Costello EK, Knight R. Forensic identification using skin bacterial communities. Proc Natl Acad Sci U S A. 2010 Apr 6; 107(14):6477-81.